Nonsparking deck tread



' slip safety treads.

Patented Apr. 11, 194s s V NONSPARKING DECK TREAD Frank M. McGeary, Washington, D. C.; and Theodore A. Werkenthin, Arlington, Va.

Application October 24, 1942, Serial hlm-463,278

2 Claims. (Cl. F75-.264)

(Granted n'naer the et of March s, 12883, as amended April 30, 1928; 370 0. G. 757) This invention relates to treads and floor coverings, particularly to such material when used in locations such as powder magazines and fuel oil handling rooms of ships, for which there has been great diiculty in nding suitable deck treads.

One object of this invention is to provide non- This is attained by the use of a latex cement covering, the surface of which has a high coefficient of friction both wet and dry. f

Another object is to provide treads that will be non-sparking when struck by metal. This is accomplished by avoiding the use of a hard abrasive surface which may tear of! tiny particles of a metallic object striking it with suilicient force Vto heat them to incandescence.

A further object is to provide treads whichare non-sparking, due to presence of static electricity. This is accomplished by use 'of a non-metallic aggregate in the latex cement covering, and providing electrical conductive connectors to the metallic structure of the ship, so that static electrical charges will be dissipated.

Another object is to provide treads which will be easily installed and readily replaceable when worn. rL'his object has been obtained by placing the above mentioned latex cement covering within a tray of hard rubber which can be secured to the deck by screws. Latex cement can be much more readily bonded to the hard rubber tray than directly to the metal deck, and the whole tread can be more readily removed when necessary.

Still another object is to provide a tread of Suitable durability in service. This is accomplished by the use of the above-mentioned tray, as its edges protect the latex cement at the point of greatest wear without causing appreciable sacrice of the desirable qualities of the latex cement.

A still further object is to provide an oil-resistant safety tread, which can be attained by using as ller for the hard rubber tray a putty of synthetic rubber such as neoprene or similar material containing an aggregate to increase its slip-proofness.

of screws placed along the edges of the tray, and by the use of a hard rubber stock havingsufcient flexibility to allow the edges of the tray to be molded by the-pressure of the screws to conform closely to the shape of the deck.

.With the foregoing and other objects in view, the invention consists in the construction, combination and arrangement of parts hereinafter described and illustrated in the drawing, in which: Fig. 1 is a top plan view, partly broken away, of the tray of this invention; and

Fig. 2 is a sectional view on line 2 2 of Fig. 1. There is shown at I0 the improved tread of this invention. This tread I0 includes a tray II- having an aggregate receiving depression I2 in its upper surface'extending to its edges I3. From' these top edges I3 the outer side Il curves smoothly down to an edge I5, forming a-slightly cupped lower surface I6 on the Abottom of the tray II, this cup edge I5 extending completely about the lower surface I6 of the tray II.

A plurality of countersunk screw-receiving apertures I1 extend through tray II adjacent the side walls of the depression I2. The tread I0 is secured to a metallic deck I8 by means of the metallic screws 20 extending through the apertures I1. Before the tray II is fastened in position on the deck, however, a cement filler 2| is placed between the bottom surface I6 of the tray II and the deck within the confines of the edge I5. A preferred composition of the filler 2| is 'w1/2% of rubber latex, 48% hydraulic cement, and the balance of accelerators, anti-oxidants, and other conventional vulcanizing ingredients. The screws 20 are then placed in position and tightened so as to press the edges I5 tightly against the deck, thus preventing any seepage of water therebeneath with consequent corrosion of the deck surface. After the tray is thus iirmly secured to the deck in its appropriate position, the depression I2 is iilled with a putty 22 of synthetic rubber such as neoprene or similar material containing a carbon-black aggregate and having a high coefficient of friction, both wet and dry. A preferred composition of this putty 22 is 30% rubber latex 30% h 25% of an aggregate of 40-60 mesh ro nd walnut shells, 12'1/2% carbon-black, and e balance of accelerators, anti-oxidants, and other conventional vulcanizing ingredients. This carbonblack aggregate makes the putty 22 an electrical conductor which is grounded by the metal screws 20 to the metal deck I8.

In operation, the treads I0 are thus assembled in appropriate position wherever needed. They are particularly useful in powder magazines or other locations where it is imperative that all sparking be eliminated. The carbon-black bearing aggregate in the putty 22 prevents accumu-l sparks when struck by any metallic object. When the putty 22 becomes worn away through constant use, it may -be easily replaced' in the same manner in which it tion. i

While the tray Il has been described as being of hard rubber, it will be understood that 'this term "rubber" includes not only the natulal-mi bers but also any so-called synthetic rubber or rubber substitutes having the desired physical properties, including well known 'plastics withv bases made uffresin, urea formaldehyde, or any other suitable material, and that the term rubber, as herein used, should -`be so interpreted'. Although specific examples vof the compositions of the iilier 2l and putty22 havebeen disclosed, any 4other suitable compositions may -be used. Some -suitabiecompositions are disclosed in Navy Department-*Bureau of Ships Specification 52-D6 (intl).

@ther modiiieations and changes' in the number and proportions 'of the `parts may be made by thoseskilledinthe: art without departing from the nature at the invention within the scope di" what is hereinafter claimed. Y

Theinvention describedherem may be manufactin'ed "andi used by crm the Governmentfof the United States or Anrerica ferrzovernmentaal mimosas `Without the :payment .of royalties thereon ortheretm'.

was originally placed inposi- Having thus set forth and disclosed the nature of this invention, what is claimed is:

1. A non-sparking deck tread comprising a c semi-flexible tray having a filler-receiving depression in its upper surface, said tray being of extenda through countersunk apertures through frebpttomidfthue 'tray depress and into the deck, and a. liquid-proof illler between 4the bottom sur- "face of the tray and' the deck, said nller being conncd between the tray and the deck by the cupped edge on the bottom of the tray, said cupped fedgebcingpressed' against the deck by the traysecming means.

2. :Anon-sparking deck tread. comprising a tray havingv `a. yiilieiwreceiving. depression in. :its upper surface, said tray being .of a, non-.sparkingnom ducting material, a, cupped edge extending about its lower sunfacesaid tray .being illled with a non- "sparking putty having electrical condting properties, means .mechanically :securing .said tray to -a metal deck, said-means electrically connecting .theicenducting putty Ato the deck,and a liquid-proof ,ller between the bottomsurface vai the tray and the deck, said filler being confined beneath'the tray. by the cuppededgethereoLsaid cuppeddge beingl pressed against thedeck by the tray-securingmeans;

.M` `Meermin-y. THEQDQRE iA. 

